Excess Epicardial Fat and Myocardial Remodeling After Mitral Valve Surgery

Objective: This study aimed to assess the relationship between excess epicardial fat and the patterns of perioperative myocardial remodeling in patients undergoing surgical correction of mitral valve (MV) disease. Methods: A total of 148 patients with acquired non-infectious MV disease scheduled for surgical correction under cardiopulmonary bypass were screened in this prospective observational non-randomized study. Preoperative computed tomography (CT) of the heart was performed to assess epicardial adipose tissue (EAT) volume. Transthoracic echocardiography (Echo), including evaluation of left ventricular (LV) global longitudinal strain (GLS), right ventricular (RV) free-wall longitudinal strain, and RV systolic function (3D Echo), was conducted preoperatively, as well as postoperatively during one year after surgery. Analysis of postoperative myocardial remodeling and complications within one year after surgery was performed. Patients were divided into groups before surgical correction of MV based on the (1) EAT volume, associated with atrial fibrillation (AF) presence (EAT volume less than or > 115.1 cm³ by CT), and (2) EAT volume, associated with the presence of at least three metabolic factors (EAT volume less than or ≥100.6 cm³). Results: Prior to MV correction, Echo showed that patients with EAT volume > 115.1 cm³ exhibited larger left and right atrial (LA/RA) volumes and more pronounced RV systolic dysfunction. An EAT volume of >115.1 cm³ was associated with a 4.6-fold increase in the odds of detecting a preoperative TAPSE value < 1.7 cm (OR: 4.6 [95% CI: 1.2543; 16.7481]; p = 0.02). In the early postoperative period, patients with EAT volume > 115.1 cm³ exhibited larger RA dimensions and higher RV end-systolic volumes, as well as impaired RV-pulmonary artery coupling. At the one-year follow-up, patients with EAT volume > 115.1 cm³ exhibited larger indexed atrial volumes and basal RV dimensions. By the one-year follow-up, the group with EAT volume ≤ 115.1 cm³ was characterized by dynamic improvements, including a 10.7% increase in LV GLS (p = 0.02), a 33.6% reduction in the indexed LA volume (p = 0.004), a 28% reduction in the LV mass index (p = 0.003), and a 10.3% reduction in the LV end-diastolic dimension (p = 0.01). Furthermore, this group exhibited a 15% increase in LV stroke volume (p = 0.009), a 17.6% increase in TAPSE (p = 0.02), and a 6.5% increase in RV ejection fraction (p = 0.04) (3D Echo), none of which were observed in the group with EAT volume > 115.1 cm³. Patients with EAT volume ≥100.6 cm³ had more pronounced impairment of LV GLS before and one month after surgery compared with those with EAT < 100.6 cm³ (p = 0.046; p = 0.045). One month after surgery, worsening of RV GLS was observed specifically in the group with EAT ≥ 100.6 cm³ (p = 0.031). By the one-year follow-up, significant improvement in RV systolic function was observed only in the group with EAT volume < 100.6 cm³. Conclusions: The presence of excess epicardial fat (verified by cardiac CT) in cardiac surgery patients with acquired MV disease is associated with less favorable preoperative remodeling of both the left and right cardiac chambers and impaired reverse myocardial remodeling within one year post-surgery. Further studies in larger, independent cohorts are needed to confirm the prognostic and clinical relevance of the EAT cut-off in patients with mitral valve disease.